Error when querying for open_source_LLM_retrieval_qa example

[dn-vcc]

I followed the example "https://github.com/ray-project/langchain-ray/tree/main/open_source_LLM_retrieval_qa", with the "Building the vector store index" and "Serving" commands as below without any problems:

python build_vector_store.py

serve run serve:deployment

But when trying "Querying"

python query.py 'What is the difference between SERVE and PACK placement groups?'

I get the following error:

Traceback (most recent call last):
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/site-packages/urllib3/connection.py", line 174, in _new_conn
    conn = connection.create_connection(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/site-packages/urllib3/util/connection.py", line 95, in create_connection
    raise err
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/site-packages/urllib3/util/connection.py", line 85, in create_connection
    sock.connect(sa)
ConnectionRefusedError: [Errno 111] Connection refused

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/site-packages/urllib3/connectionpool.py", line 703, in urlopen
    httplib_response = self._make_request(
                       ^^^^^^^^^^^^^^^^^^^
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/site-packages/urllib3/connectionpool.py", line 398, in _make_request
    conn.request(method, url, **httplib_request_kw)
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/site-packages/urllib3/connection.py", line 244, in request
    super(HTTPConnection, self).request(method, url, body=body, headers=headers)
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/http/client.py", line 1286, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/http/client.py", line 1332, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/http/client.py", line 1281, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/http/client.py", line 1041, in _send_output
    self.send(msg)
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/http/client.py", line 979, in send
    self.connect()
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/site-packages/urllib3/connection.py", line 205, in connect
    conn = self._new_conn()
           ^^^^^^^^^^^^^^^^
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/site-packages/urllib3/connection.py", line 186, in _new_conn
    raise NewConnectionError(
urllib3.exceptions.NewConnectionError: <urllib3.connection.HTTPConnection object at 0x7f06d13f2950>: Failed to establish a new connection: [Errno 111] Connection refused

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/site-packages/requests/adapters.py", line 486, in send
    resp = conn.urlopen(
           ^^^^^^^^^^^^^
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/site-packages/urllib3/connectionpool.py", line 787, in urlopen
    retries = retries.increment(
              ^^^^^^^^^^^^^^^^^^
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/site-packages/urllib3/util/retry.py", line 592, in increment
    raise MaxRetryError(_pool, url, error or ResponseError(cause))
urllib3.exceptions.MaxRetryError: HTTPConnectionPool(host='localhost', port=8000): Max retries exceeded with url: /?query=What%20is%20the%20difference%20between%20SERVE%20and%20PACK%20placement%20groups? (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7f06d13f2950>: Failed to establish a new connection: [Errno 111] Connection refused'))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/oia2ml/Llama-2/langchain-ray/open_source_LLM_retrieval_qa/query.py", line 6, in <module>
    response = requests.post(f"http://localhost:8000/?query={query}")
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/site-packages/requests/api.py", line 115, in post
    return request("post", url, data=data, json=json, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/site-packages/requests/api.py", line 59, in request
    return session.request(method=method, url=url, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/site-packages/requests/sessions.py", line 589, in request
    resp = self.send(prep, **send_kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/site-packages/requests/sessions.py", line 703, in send
    r = adapter.send(request, **kwargs)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/oia2ml/anaconda3/envs/ray/lib/python3.11/site-packages/requests/adapters.py", line 519, in send
    raise ConnectionError(e, request=request)
requests.exceptions.ConnectionError: HTTPConnectionPool(host='localhost', port=8000): Max retries exceeded with url: /?query=What%20is%20the%20difference%20between%20SERVE%20and%20PACK%20placement%20groups? (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7f06d13f2950>: Failed to establish a new connection: [Errno 111] Connection refused'))

Tried to troubleshoot with some different changes (IP and firewall) but could not solve out the problem.
Could you please advise on this matter?
Thank you.